


anchored to this shore

by ichinoseharu (rinsousukes)



Category: Free!
Genre: First Time, Interspecies Sex, M/M, Sousuke is very proportionate (in case you were wondering), merman dick, mythical creatures AU
Language: English
Status: Completed
Published: 2015-01-26
Updated: 2015-01-26
Packaged: 2018-03-09 04:53:42
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 13,230
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3236999
Author URL: https://archiveofourown.org/users/rinsousukes/pseuds/ichinoseharu
Summary: <blockquote class="userstuff">
              <p>“Don’t say embarrassing shit like that, you overgrown fish.” he grumbles, but he doesn’t pull away from Sousuke’s hands or the warm solidity of his form, pressed to Rin’s side like a promise.</p><p>“Overgrown fish?” Sousuke looks mildly affronted and (in Rin's opinion) rather reluctantly impressed. He really shouldn’t be, because Rin could record in a thick notebook the number of creative (if he did say so himself) and rather pertinent names he'd come up with for Sousuke in the ten years or so that they’ve known each other.</p>
            </blockquote>





	anchored to this shore

“What are those?” 

Rin has to bat irritatingly quick fingers away from the neatly tied bunch of candles before they get knocked loose. It wouldn’t be much fun digging for the slender sticks in the mess of fine sand after all. It’s not like anyone but Sousuke would be around to witness that spectacle, but he has no particular desire to look like an utter idiot in front of even Sousuke this time; especially not when he has some lofty ideas in mind for how tonight should go.

“Don’t-“ He swipes the cheap lighter away from Sousuke’s reach and flips it around before enabling the safety lock. “Don’t touch this.”

Sousuke’s infernal inquisitiveness has hardly ever bode well for him (the one exception being the time he’d swum too-close to the rocky shore to return a distraught eight-year old Rin’s shark plushie) and he just knows that Sousuke would be acquainted with fire in the worst way possible if he let him get his hands on the lighter.

He waves the shiny red plastic around admonishingly but it seems to have just the opposite effect on Sousuke. His wide eyes (bright with a child-like curiosity that looks a little misplaced against the chiseled curve of his jaw and his high cheekbones) follow the movement of the lighter and he paws at the air in an attempt to reach it.

Rin just sighs and tosses it into the stretch of sand behind him, well out of reach of the grabby little shit. When Sousuke’s brows knit beseechingly, he just shoots him an irritated look.

“Don’t be a nosy little fucker. Didn’t I tell you this was supposed to be a surprise?” He rolls his eyes when Sousuke fixes him with a mildly irritated look. “This is why I told you to come  _after_  the sunset.”

“It’s setting now anyway, Rin. Don’t be a grouch.” Sousuke just rests his forearms on the cool sand and props his chin on them, watching Rin with preternatural focus as he smooths out a patch of sand with his palm before setting the brass candelabrum down firmly. He’d felt a little silly lugging the heavy contraption all the way to the beach, but Sousuke’s wondering gaze makes him feel like the extra bit of effort had been worth it.

“Since you’re here, it can’t be helped. Help me lay out these plates.” He holds the fine china out of Sousuke’s reach when he grabs at them. “And be careful with them! Ma doesn’t know I took them.”

Sousuke just shoots him a grumpy look and mumbles something (doubtlessly a few choice words about Rin’s attitude) under his breath.

“What was that?”

“Nothing.”

“Thought so. And c’mon, let’s get you further back in. The tide’s going out.” A patch of turquoise on the uppermost part of Sousuke’s tail, right where smooth, tanned skin blends into the rough of scales, is getting white-ish and dry.

Rin rolls up the hem of his new khaki chinos (the gesture born more out of habit than anything, since sand has already caked the most part of them) and then steps around Sousuke and into the foam of the sea water to heft Sousuke’s torso up with a grip under either of his arms. It leaves him tremendously winded, the exertion of having to move the combination of his ridiculously muscled upper body and dense tail.

When he’s done, he steps back to survey the luminescent sparkling of Sousuke’s tail scales as the water sluices over them. Sousuke’s entire form is outlined by the ruddy glow of the dusk and the shining turquoise of his tail stands out in stark contrast against the murkiness of the seawater and the pale sand. He’s even more beautiful than Rin had thought him to be ten years ago, when he’d first laid eyes on this strange hybrid of man and fish in this exact alcove.

Rin doesn’t allow himself to fix his gaze too long on the thickness of his biceps, the tantalizing column of his neck and  _especially_  not the way the slick of his tail right below his lower abdomen dents and leads into a – well, he’s not entirely sure, but he’d be damned if he wasn’t going to find out soon.  

Because Sousuke is nothing if not perceptive, and he’d immediately single out the reason for Rin’s distractedness and tease him mercilessly for the rest of their time together (years, decades even). Rin swallows a little uneasily when he thinks about how much trouble he’d be in if Sousuke discovered his true intentions for the night.

“Hey, I told you to be careful with those. And don’t let the sea water touch the plates, you idiot.”

He pulls out the containers of Tupperware from his backpack, pointedly ignoring Sousuke’s exasperated glare, all the while keeping an eye on his clumsy handling of the fine china plates and clear glasses. When he lays the Tupperware out on the sand in front of him, it strikes him that it’s probably terribly unromantic to serve messily packed food during candlelit dinners. But one glance at Sousuke’s restlessly swaying tail leaves his worries assuaged. Nothing about Sousuke, Rin or their relationship is decidedly normal or conventional, so this will have to do.

It’s the thought that counts after all, he tells himself, but his palms begin sweating anyway, with the possibility of what could transpire next if all went as planned.

“Done.” He tells Sousuke, who’s taken to drawing senseless little shapes into the sand with his fingertips as his eyes follow Rin’s motions fascinatedly.

Sousuke pokes at the silver fork and knife laid out on serviettes beside his plate curiously.

“What are these, Rin?”

Rin's smiles reluctantly at his wide-eyed confusion.

“Eating utensils. We don’t just gulp down fish like you guys, we use these to cut them up into portions first.”

Sousuke snorts and gives Rin a disbelieving look. “Why would you wanna do that?”

Of course he wouldn’t understand. Rin chides himself a little for being a little too pretentious: at least with a merman who knew shit all about human practices. Maybe the cutlery hadn't been the best of his ideas.

“Forget it. You just use your hands, alright?”

But Sousuke guards the fork and knife carefully, cupping them with large palms. His eyes are fixed firmly on the silvery gleam of them.

“They’re shiny.” He wonders, and then grins up at Rin with newfound enthusiasm. “I’ll use them!”

For such an imposing and admittedly regal creature, his mannerisms are strangely adorable at times. Rin has learnt that these glimpses of wide-eyed inquisitiveness and candour and  _vulnerability_ that he shows Rin are more than special, because Sousuke is doubly wary and sometimes even aggressive towards humans who occasionally poke around and try to upset the tranquility of the alcove. Rin has personally witnessed several instances of too-nosy schoolboys tucking tail and booking it out of the area after catching a glimpse of Sousuke’s dark, irritated eyes and rather impressive snarl.

He reaches in front of him to stroke a gentle hand down the roughness of Sousuke’s lengthy tail, careful not to knock over the candelabrum between them.

“Yeah, fine, I’ll teach you how to use 'em, you big doofus.” He tells Sousuke, only to be completely ignored, because Sousuke’s attention has drifted to the plate of pan-fried dory set before him and he’s sniffing at it, the gentle swishing of his tail increasing in vigour as he realizes it’s fish, albeit a different sort than he’s used to. Cooked, for one.

“I just caught a bunch of these for Mam last week.” Sousuke says happily, and Rin ruffles his rapidly drying, gravity-defying hair fondly.

“Yeah, and now you get to taste the Matsuoka Rin Special. You should be feeling pretty lucky right now, man.”

“I really doubt that, somehow.” Sousuke squints at the stir-fried bits of vegetable that Rin’s spooning onto his plate and pokes at the stalks of leek with a fingertip until Rin slaps at his scaly knuckles.

“What’s that? Seaweed?”

“It’s called leek. And how many times do I have to tell you to stop messing with the food?”

“Grumpy..”

When he’s finally finished with arranging the food onto both their plates and pouring sparkling water into the glasses, he reaches back for the lighter and turns off the safety lock before lighting each of the candles carefully. He takes extra caution to keep them far out of Sousuke’s reach as he reaches out to fix them onto the candelabrum, especially when he notices Sousuke’s infernally inquisitive gaze following the embers closely.

When he's done, he sits back on his haunches and appreciates the view for a minute or two. Dusk has started to settle in and the last vestiges of sunlight are fading into the horizon, shading the sea a deep blue-black. The warm golden glow of the candlelight makes the rather hasty set up of plates and cutlery look rather classy, Rin thinks smugly. It isn’t like Sousuke is going to care much for these finer aesthetic details either way, but Rin’s inner perfectionist rejoices nevertheless, at the unexpected turn out.

He’d been preparing for the worst over the last week or so, ever since he’d come up with the seemingly ingenious plan (not one of Rin’s more rational ideas, truthfully) of having a candlelit dinner by the beach.

The possible disasters waiting for him in the course of the dinner had been painful to even contemplate or enumerate. An unexpected high tide, pesky seagulls,  _Sousuke getting bored_  – Rin isn’t going to pretend the last one hadn’t weighed unexpectedly heavily on his mind.  

But Sousuke’s eyes are the kind of impossibly shiny turquoise that they usually are when he’s feeling safe and happy and the toothy, gleeful smile he sends Rin’s way once he pops a morsel of the fish in his mouth is enough to lay to rest the most part of Rin’s worries. Throwing aside his pride to ask Gou for help with the preparation of the food this afternoon, stealing Mama’s dining set (he’s going to get chewed out well and good for that one), worrying for days’ end about whether Sousuke would find this a ridiculous outpouring of  _human_ sentiment, it had all been worth it.

It’s all worth it  _now_ , when Sousuke reaches forward to lace his fingers with Rin’s and then slides his thumb over the back of Rin’s hand so softly, over and over again. Rin smirks back at him because if he doesn’t, he’s sure that he’s going to say something disgustingly sappy and ruin the moment.

“Used your fingers, did you? After all that talk about trying out the cutlery?” He clicks his tongue and tugs his fingers away from Sousuke’s, easing out of his cross-legged position to squeeze in beside Sousuke and guide his hands to the fork and knife.

But Sousuke seems to have recognized the emotions at play within him. He’s surprisingly sharp like that. He grips Rin’s hand again, and squeezes hard, hard enough that Rin can almost hear the fine bones of his hand squeak in protest. Sousuke becomes less mindful of his own strength when he gets particularly caught up in the moment, but Rin squeezes back, giving as good as he gets.

“Thank you, Rin.” His voice is soft. “I know we don’t do this often. But I really do love spending time with you.”

Rin looks away sharply to hide his rapidly flushing cheeks. Sousuke and him don’t usually do this. Talk about their  _feelings_  and all. They’d been best friends long before they’d become lovers after all, and there’s still a conspicuous sort of awkwardness about recognizing the emotions at bay during situations like these, with putting words to the bone-deep, all-encompassing kind of love that they  _know_ they have for each other _._

That’d been the main reason he’d been apprehensive about this stint.

But he can’t say that he’s not tremendously pleased by this, warmed to the tips of his fingers by the sincerity and honest emotion in Sousuke’s voice.

“Don’t say embarrassing shit like that, you overgrown fish.” He grumbles, but he doesn’t pull away from Sousuke’s hands or the warm solidity of his form, pressed to Rin’s side like a promise.

“Overgrown fish?” Sousuke looks mildly affronted and (in Rin's opinion) rather reluctantly impressed. He really shouldn’t be, because Rin could record in a thick notebook, the number of creative (if he did say so himself) and rather pertinent names Rin had come up with for him in the ten years or so that they’ve known each other. 

“Overgrown, huh." Sousuke mutters lowly. “Wouldn’t you like to find out.”

 Rin jerks his head back to him so quickly that he just barely manages to avoid giving himself whiplash.

“What? What did you say?”

“Nothing at all, Matsuoka. Now are you gonna teach me how to use these or should I toss them right over there for Momo to find?” He makes a quick jerking motion, as if to throw the ridiculously expensive cutlery into the deep of the swirling waters.

 Rin flicks him hard on the side reproachfully.

“You do that and I’ll drag you home, tail and all, for you to explain to Mama why her favourite set’s missing a knife and a fork.”

“As if you could even move me an inch if I didn’t want to be moved.”

Rin gives him an offended look and flexes his biceps pointedly. He’s pretty proud of them, especially because he’s been spending a lot more time at the gym lately.

“We’ll see about that, won’t we? And I can always give Makoto a call and ask him to bring a gunny sack and a cloth gag if you’re being particularly difficult.”

When he notices the challenging glint that's risen up in Sousuke's eyes though, Rin sighs and decides to let up, because as much as he hates giving in to Sousuke and as much as his own competitive spirit is beginning to kindle inside of him, today is really not the day for this.

“Hold that thought, we’ll test it on another day. Now, c’mon, first you gotta slide your index finger onto the blunt edge of the knife and grip it just about-“ He manouevres Sousuke’s big fingers till they’re gripping the knife with some semblance of normalcy. “Here.”

Sousuke seems to enjoy the fish (he’d attempted, with minimal success, to use the knife to cut it up, until Rin, frustrated with the spectacle and terribly distracted by Sousuke’s tongue poking out of the side of his mouth in concentration, had grabbed the cutlery and tossed it to the side) if not so much the vegetables.

His fascination with the sparkling water (“Rin! It’s ambrosia, it must be!”) is also more than a little entertaining to witness and Rin’s heart beats in a strangely irregular rhythm for the rest of their meal, too full with the kind of overwhelming fondness that he reserves specially for this paradoxical hulk of a merchild.

The fish, even though he doesn’t particularly enjoy the lean morsels, tastes sweeter on his tongue than it ever has before.

 

-

 

Rin’s tummy is pleasantly full and warm after, and when he gazes up at the vast spread of shiny shapes in the night sky, it feels like he’s been put into a trance. His mind is refreshingly blank for once, and even the clatter in the background (Sousuke tinkering with the candelabrum) can’t seem to draw him away from the agreeable haze that clouds his thoughts.

He’s feeling a lot less nervous now about his _plan_. Being around Sousuke does that a lot: assuages needless worries and gentles the intensity of the neurotic phases that Rin’s exceedingly prone to whenever he’s of minds to tackle something new.

It doesn’t need to be awkward or tentative between them anyway, Rin reasons to himself, because this is  _Sousuke_ and Rin has patted his back through bouts of severe vomiting after he’d foolishly bit into a puffer fish at ten, seen him with despondent tears streaking his cheeks when his Dad had been wounded by a stray harpoon at fourteen, made him flower wreaths to hand to the pretty mermaid up on the other side of the shore when at sixteen, Sousuke had developed the most terrible crush on her. 

It’s  _just Sousuke_ , the same Sousuke who’s held him at his snuffling, wailing worst, at his most awkward and his most depressed. Just Sousuke, and that’s more than enough to get Rin’s spirits up again, because Rin _knows_ him, knows him better than he's known anyone else. _  
_

He reaches behind him blindly and feels around until the pads of his fingers scrape against the rough of tail scales. And then kneads against solid muscle, hard enough that it jumps under his touch. Sousuke makes an irritated noise.

“What?” His attention is already back on the candelabrum by the sounds of it, and Rin scowls.

“The secrets of the universe aren’t in that thing, you know. Give it a break and c’mere for a while.”

He hears Sousuke breathe out a put-upon sigh, likely for Rin’s benefit, and then he’s awkwardly sliding across the sand until his side is pressed to Rin’s own. The heady warmth of the contact and the affectionate brush of Sousuke’s tail against his calves shake Rin out of his contemplative mood. He swallows.

“What now, Rin?”

“The stars are beautiful aren’t they?” Rin blurts out. And then wants to ram his face into the sand, because that’d been _lame_ , even for him.

Sousuke snorts and starts laughing, the vibrations of his torso bleeding into Rin’s own and sending renewed shivers through him.

“ _The stars are beautiful?_ Really, Rin? You haven’t noticed that the last, I dunno,  _five hundred times_  we’ve been here?”

“Shut up, you moron.” Rin growls agitatedly, passing a palm across his burning face. “I was just trying to set the mood.”

He winces immediately, because he hadn’t meant to let the latter part slip and he’s not nearly ready to handle Sousuke’s inevitably mounting curiosity.

“Set the mood?” Sousuke props himself up with an elbow on the sand to inspect Rin’s pink cheeks. “What mood?”

“Forget I said that.” Rin mutters, hiding his eyes with a forearm and deliberately avoiding Sousuke’s calculating gaze. It doesn’t deter Sousuke in the least though, just as Rin had expected. He pries Rin’s arm away easily and regards him thoughtfully for a moment, taking in Rin’s jitteriness and obvious embarrassment.

“You sly dog.” He exclaims, after a moment of silence. His eyes are alight with amusement and a tinge of what almost looks to be anticipation. “You lured me out here with the promise of a fish dinner, but you really just wanted to take advantage of me, didn’t you?”

He doesn’t even let Rin interject, barreling on.

“You could’ve just told me that from the start. You didn’t have to do all this.” Sousuke pauses to grin at him. “Not that I didn’t enjoy it. I really did. But I swear, you humans and your coquettishness.”

Rin groans, wishing now, more than ever, that the expanse of sand would just open up and swallow him whole, so that he wouldn’t have to continue looking at the dawning realization and plain amusement in Sousuke’s bright eyes.

“Oh my god, Sousuke, shut up!” Then, he blinks, recalling Sousuke’s unfortunate choice of words. “And  _who’s_  taking advantage of  _who_!”

“Obviously you’re trying to take advantage of my innocence.”

“Have you even looked at yourself in the mirror? Who the hell could take advantage of you!” He’s not even going to touch on the innocent part, because even Sousuke should have realized the ludicrousness of his own claim.

“We don’t  _have_ mirrors under the sea, you uncultured fool.”

“Well, you have shiny rocks and- Wait, that isn’t even the point!” Rin grumbles, looking resolutely to his right, away from Sousuke’s needling gaze, where fine drops of condensation are already beginning to build up on the dark surfaces of the rocks flanking the alcove.

“So.” Sousuke hums, in the ensuing almost-awkward bout of silence. When Rin doesn’t look at him, he clamps two fingers around the jut of Rin’s chin and tilts his face to him easily. Rin doesn’t even bother to struggle. He’d learned several years ago (after a particularly unfortunate tickling session) that when it came to physical strength, Sousuke had the staunch upper hand.

Freaky merman strength, he thinks bitterly.

“So.” Sousuke picks up where he left off. “Are you going to make an honest mer _man_ out of me later or..?"

Rin elbows him sharply in the side, irritation and helpless amusement warring within him.

“Okay, kidding, kidding!” Sousuke catches his wrist in a loose, warm grip and holds it to his chest. It’s really a pretty unfortunate move on his part, because Rin is already distracted by the firmness of those ridiculous pecs and more importantly, the quick thump-thumping of his heart within.

“You’re nervous!” Rin marvels, flattening his palm against the expanse of his chest, and as if in answer, Sousuke’s heart speeds up just that little bit more under his touch. “You are  _so_  nervous right now.”

He grins at Sousuke, feeling a lot less embarrassed now that he’s found the crack in Sousuke’s seemingly impregnable armour.

“No, I’m not.” Sousuke mutters sulkily. But he must have realized the futility of his own reply, because a tint of pink crawls onto the jut of his high cheekbones. Rin’s grin widens at that. Sousuke could really give him a run for his money when it came to the lack of candour in admitting pesky feelings and such.

“So, listen. I’m gonna admit that I  _did_ have an ulterior motive.” He holds up his palm and makes an annoyed sound at the back of his throat when he sees the triumphant gleam in Sousuke’s eyes. “But. But I also really just wanted to spend time with you. Like this. We don’t have to do anything after.”

His cheeks are on fire again. It might just be a permanent state for tonight, he thinks wryly to himself, and out of misplaced irritation, curses his fair complexion.

Sousuke’s eyes soften and he props his head on a palm, looking down at Rin with that wretched expression, the one where his eyes became all droopy at the corners and turned almost liquid with fondness and a tiny smile curved at his lips. The same expression that’s set Rin’s heart racing ever since he’d turned thirteen and really started  _noticing_  Sousuke as more than just a best friend or a silly playmate.

He has to swallow to ward off the sudden dryness in his throat.

“Me too, Rin. I always want to spend time with you.” Sousuke murmurs. Rin watches fascinatedly as his Adam’s apple bobs, like he’s steeling himself to say something.

“But I also want to do  _this_  with you.”

He barely gives Rin a warning before swooping down and catching Rin’s bottom lip between his own. His mouth is hot against Rin’s own, and his lips are incredibly soft when he slides them across Rin’s. Rin is stunned into inaction for a couple of seconds, but then he sighs into the kiss and brings up a hand to cup the back of Sousuke’s head and press him closer.

“Ufgh stase lgh-“ Sousuke’s mumbling something into his lips and Rin rolls his eyes, reluctant to part from the heady, slick warmth of his mouth, but doing so anyway.

“Talking while kissing? That’s a new low even for you.”

Sousuke glares at him.

“I  _was saying_ that you taste nice. Like fish. But I take it back now. You taste like that old patch of algae that Gramps grows in his garden.”

“You actually have  _gardens_  underwater? And yeah, yeah, you taste nasty too, bla bla. Now shut up and kiss me again.”

Sousuke, in a surprising bout of compliance, does exactly that.

He leans over Rin with his entire torso, blocking out the glimmering light of the stars above, and encompassing Rin with his ridiculous warmth. He really is like a space heater.

This time, he brushes his tongue over Rin’s lips, and Rin lets out a surprised little noise, parting his mouth to let Sousuke in. Sousuke’s tongue is rougher than the average human’s when it slides over the inside of his cheek and his fingertips are impossibly hot where he’s thumbing over Rin’s hipbones through his thin t-shirt.

Someone’s making a tiny, almost-hurt sound into the kiss and Rin startles when he realizes that it’s coming from his own throat. Sousuke just hums in response and moves to press his chest more firmly to Rin’s, half-lying over him awkwardly. His tail is swaying softly, brushing up wetly against the smooth skin of Rin’s calves and raising goosebumps on it.

His torso is heavy, even though he’s clearly holding off part of his weight, but Rin welcomes the reassuring solidity of it. He thinks he quite likes this feeling of being trapped under Sousuke, with his warm arms caging Rin in and his mouth hot against Rin’s own.

Rin doesn’t even mind the grains of sand creeping inside his t-shirt and sliding distractingly against the skin of his back. When Sousuke’s mouth parts from his with a slick sound and trails down his jaw, he has to bite back an embarrassing sound.

Sousuke’s teeth are warm and gentle against the sensitive skin of his neck and when he bites down softly at the spot where his pulse is thrumming, Rin arches into the touch, sliding his arms around Sousuke’s neck and pulling him even closer.

His legs seem to have a mind of their own, and as his belly heats with desire, they shift to the side to wrap around the solid girth of Sousuke’s restlessly twitching tail. His feet come up to rub up against the sand-paper rough scales littered over the length of it; the sensation is curious, the sensitive soles of his feet tingling with it.

He makes a sharp, keening sound when Sousuke shudders at his motion and bites at his neck again.

“Fuck.” Sousuke mutters. His voice is gravely and unfairly attractive. “Do that again.”

“Do what again?” Rin pants, guiding Sousuke’s lips back to his with a palm to his cheek. “This?”

This time, he scrapes the points of his toes deliberately across the midsection of Sousuke’s tail, licking into Sousuke’s mouth determinedly all the while. Sousuke jerks into the motion and his eyes flutter closed.

When he opens them again, Rin notices immediately that his pupils are diluted and clouded over by a strange, silvery sheen.  The blue ringing them is bright and clear. He isn’t smiling.

Rin has to hold in his surprised gasp at how intense he looks right then, like this isn’t enough, like he wants to crawl into Rin and possess him.

Rin honestly wouldn’t mind, not at this point, at least. He’s too far gone to notice anything but the press of Sousuke’s bare, hot skin against his own through the thin layer of his t-shirt and the oddly arousing roughness of his tongue as it slides into Rin’s mouth.

When Sousuke shifts and heaves his tail up to slide it between Rin’s legs, Rin bucks up into him and winds his legs fully around it, ankles locking at the spot on Sousuke’s back where tanned skin blends into the rough of shiny turquoise.

He flushes though, when it comes to his notice (and most likely Sousuke's too) that his half-hard dick is prodding persistently into Sousuke’s tail where it’s pressed against.

Sousuke rips his mouth away from Rin’s, breathing heavily, mouth red and swollen and hair in disarray from Rin’s fingers carding through it. He rolls his lower body forward in a sinuous motion, mouth parted in concentration and Rin groans at the delicious pressure against his dick.

“Oh fuck.” He gets out, his lower belly near-cramping with the sudden intensity of his desire. “Fuck.”

Sousuke just does it again, and Rin reaches up to smatter desperate kisses over the gleaming expanse of his neck. His tooth snags at the soft skin and he nudges in, worrying at the spot until it feels hot against his lips. Sousuke’s breathing gets heavier, Rin can feel it, wet and hurried against the skin of his ear.

And it’s then that he picks up on the press of something hard and insistent against the inside of his thigh. He pulls away from Sousuke’s neck to look down between them, confused by the pressure that clearly hadn’t been there before, and when he finds what he’s looking for, his eyes widen in surprise.

His blood thrums through him in a delicious cocktail of arousal and electric desire, because Sousuke’s dick is bare and hot and  _huge_ even against the thick material of Rin’s chinos and it burns a heady warmth into the crook of Rin’s left thigh where it’s pressing against. It's emerging from the thin slit in the upper part of his tail that Rin had been inspecting earlier, and a flash of clarity and understanding passes through his muddled brain.

“Wow.” He mutters, still reeling from the discovery. “Where did  _that_  come from? Are you sure that’s your dick? Looks more like a harpoon.”

Sousuke’s eyes, which were boring into Rin’s own, serious and luminescent with desire, crinkle at the corners. He starts laughing, and it completely transforms his expression. Rin can’t believe this is the same Sousuke from before, the one who’s eyes had been sharp enough to cut through glass, who’d looked like a stranger, who’d seemed almost  _dangerous_  in all his intensity.

“Way to ruin the mood, idiot.” He snorts, and then looks a little sheepish. “That really is it, though. You should touch it, just to make sure.” He waggles his eyebrows suggestively and Rin breathes out a reluctant little laugh.

“That was terrible. If you wanted me to touch you, you could’ve just asked like a normal person.”

He reaches down between them, ignoring Sousuke’s shocked intake of breath (he clearly hadn’t been expecting Rin to take him up on his offer so quickly), and slides his fingers around the rigid upward slant of his dick.

Sousuke bucks against him desperately, nearly unbalancing himself from his position atop Rin, but Rin barely notices, too caught up in the smooth, almost-rubbery feel of it against his fingertips.

It’s thick and long, a portion uncovered even though Rin’s palm is fully wrapped around it, and it twitches when Rin strokes it absently. There’s no foreskin creasing the tip of it, and Rin’s surprised to discover that apart from the vaguely pointed tip and the almost conical shape of it, it’s more or less identical to his own. He’s a little relieved by it, but mostly desperately turned on.

Sousuke seems to be in a similar predicament, because his tail thumps against the ground agitatedly, displacing water from the shallow shore and wetting the material of Rin’s chinos. The cold of the seawater is shocking, but in contrast, Sousuke’s dick burns deliciously hot in Rin’s palm now, and Rin’s own twitches against the confines of his chinos in a visceral reaction.

“I’ve got to-“ He tries to wriggle out from under Sousuke. “Got to get my pants off.”

Sousuke complies and shifts to the side, making a soft, hurt noise when his dick slips out from Rin’s grip and slaps against his own abdomen. Rin misses the blanket of his warmth almost immediately. He’d barely noticed the briskness of the night air before, not with Sousuke wrapped around him, but he does now, and his scalp is chilled by the cool sea breeze.

His desire makes him clumsy and awkward, and he struggles with the buckle of his belt until finally, he just gives up and wrenches his pants down violently, the close drag of them almost painful against his hips and thighs. When he finally wriggles out of them and tosses them to the side, he notices Sousuke propped up on his side, hand wrapped around his dick and watching him with the same, magnetizing intensity that he’d been channeling before.

Rin'd thought Sousuke would have gotten a kick out of watching him fumbling around and acting like a lust-crazed fool in general, but there’s not a trace of amusement to be found in Sousuke’s beautiful eyes, just white-hot desire. It only fuels his own urgency, and he shrugs out of his t-shirt and his briefs, reaching for Sousuke with open arms soon after.

Sousuke heaves himself up and braces himself with a forearm on either side of Rin’s head, but the layers of fine sand dent under the sheer weight of him and his torso comes weighing heavily on Rin’s own, the girth of his dick burning into the skin of Rin’s thigh, brushing lightly against his balls.

Rin draws in a sharp breath at the contact, but when he looks up at Sousuke, he’s momentarily spellbound by the oddly regal look of him: the moonlight shades the tips of his dark hair almost blue and his tail scales, turquoise and bright by the day, are rendered silvery and luminescent by the gentle light.

He looks nothing like the sometimes awkward, easily beautiful creature that he is in the day, when he’s splashing about the shore playfully or dragging a complaining Rin into the cool of the ocean. A sort of sudden realization strikes Rin just then; that this is a completely different side of Sousuke, new and alien to him. He’s never quite considered Sousuke as hailing from a different world from Rin, because to Rin, Sousuke is his best friend, a constant in his life. But it’s different now, the way Sousuke looks at him, almost like Rin’s prey under his weight, like he wouldn’t let Rin go for the treasures in all the coves of the world.

Rin kisses him hard and fast, reeling with the knowledge of it, and Sousuke must have sensed his growing desperation because he licks inside Rin’s mouth with equal fervour, thumbing at Rin’s quickly-hardening nipples. Rin has to grip onto the solid points of his shoulder blades to keep from bucking up hard.

The sensation of Sousuke’s muscled, heavy tail shifting between the cradle of his thighs is unbelievably erotic, and Rin almost feels embarrassed about the heady sensation thrumming through his veins, induced by his partiality for Sousuke’s rather fantastical form.

He can already imagine it, his classmates playing a round of Truth or Dare during their graduation party (it’s in about two months or so) and an obligatory round of “Describe your first sexual experience” ensuing.  Rin has a feeling he’s going to have to sit that one out. It might be turning him on to the point of insanity at the moment, but he doubts a description of Sousuke’s massive tail and his  _very_ proportionate dick would fly well with his classmates.

It’s hardly of matter to him now though, because Sousuke’s mouth is on his nipple and Rin can feel his dick thrumming with blood and slip-sliding against his inner thigh, dangerously close to his own bobbing erection. There’s a viscous, clear fluid seeping intermittently from the tip of it, and Rin supposes that it’s the human equivalent to pre-cum, just more copious and slippery.

Oddly enough, when Rin glances down between them, the skin of Sousuke’s dick, which had been dry and smooth to the touch before, seems to be coated with a fine, filmy layer of liquid, and it smears across Rin’s thighs every time Sousuke instinctively rolls his hips down into his own. His thighs are messy with the slick and hot bolts of arousal spark in Rin’s lower belly every time they slide against each other and trap just the tip of Sousuke’s dick between them.

“What  _is_  that, dumbass?” He manages to pant out between trying to keep up with Sousuke’s increasingly vigorous motions. Sousuke turns to him, vaguely confused, his eyes almost completely shaded over by that metallic hue. When Rin slides his hand down his sweat-slick abdomen (Sousuke’s skin is strangely dry, except the patches where Rin’s sweat has reached) and rubs the pad of his thumb over the slick coating his dick, Sousuke raises a bewildered eyebrow at him.

“That’s just what happens. To make it easier for both of us.” He wraps his own large, fine-boned hand around Rin’s dick testingly and frowns, ignoring Rin’s desperate, aborted moan.

“How come yours doesn’t have it?” He squints at Rin for a moment, his motions slowing as he bites his lip a little thoughtfully.  Rin’s eyes follow the motion, his own tongue swiping at his bottom lip in sympathetic desire. But then Sousuke’s eyes crinkle mischievously and he smirks at Rin. “Guess we know what’s going in where, then.”

It takes Rin a moment to get it, thanks to the heady thrum of desire clouding his senses and rendering him incapable of rational thought, but when he does, he flinches and turns wide eyes up to Sousuke. His heart doubles its already ex-tempo beat.

“No.” He groans. He peers down between their bodies, taking in the considerable difference in size between his almost-painful dick and Sousuke’s, where they’re pressed together. “No fucking way.”

“Guess today’s your lucky day, baby.” Sousuke shoots back, eyebrows waggling in that insufferable motion of his, and Rin almost whimpers in agitation.

Runs the location of the nearest hospital from the beach through his mind. Just in case. Explaining a situation like _that_  though.. If the news spread as fast as it usually does in a small town like Iwatobi, he’s pretty sure that he’s going to have to change his name, construct a new identity and move to Brazil or just somewhere far,  _far_  away.

 **Swimmer, 18, suffers from life-threatening sex injury, unknown cause**. Yeah, he doesn’t like the thought of that headline very much.

But when he looks up at Sousuke’s earnest eyes, his steely resolve begins cracking at the edges. Sousuke’s warm, warm palm is rubbing at his flank in a soothing motion, up and down, up and down, and the panic from before slowly bleeds out of Rin.

“We don’t have to do  _that_ , Rin.” He murmurs, his free hand cupping the side of Rin’s face and thumb smoothing at Rin’s sweat-slicked bangs. “You can do it to me, even. I really don’t mind. Or we can just skip it entirely.”

Rin’s heart leaps into his throat at the unfamiliar note in his voice (he’s only heard it a couple of times in the entire ten years that he’s known Sousuke). It’s a deadly combination, the warm voice and that soothing touch. Makes him want to do things he’d never even have dreamed of doing before.

Then, Sousuke smirks at him again, leaning down to breathe softly in Rin’s ear. The motion sends tremors through his body and the wetness of Sousuke’s breath on the sensitive inside of his ear makes his dick jump in anticipation.

“I mean, if you’re this scared, we can alwa-“

Rin bristles.

“I’m  _not_  scared!”

Sousuke starts laughing, shifting his forearms to either side of Rin’s head to cage him in. Rather than making him feel trapped, it just makes him feel safe. Like if Rin willed it hard enough, they’d be ensconced in the freshness of the night air, the combined warmth of their bodies, for the rest of time.

“You’re so predictable, Rin-Rin.”

Rin decides that he’s done rising to Sousuke’s bait. At least for today. He’s going to make sure he pays Sousuke back, well and good, for this one.

“Just quit it, and come here.” He pulls Sousuke’s mouth back down to his own with an insistent arm around his neck, and muffles his tiny sound of surprise.

When he’s swallowed Sousuke’s moans with a swipe of his tongue inside his warm, wet mouth, he tugs away from him to leave just an inch between their lips. And then holds Sousuke off with strong fingers to his shoulder blades when he tries to lean in again.

“Wait.” He mutters, trying in vain to keep the red from rising up to the tops of his cheeks. “Listen. You can do  _that_  to me.”

Sousuke blinks at him, doubtlessly a little confused by Rin’s sudden change of heart.

“You sure? I meant it when I said that you could do me, y’know?”

“Yeah, I know, I know, and you better ready your ass – or your fish hole, whatever that is – for me the next time, but today I just-“ He breaks off, because he can feel his cheeks heating to an abnormal degree and his bold words get stuck in his throat.

“You just?”

Rin kisses him again out of desperation, and partly to get himself under control again, clamping his teeth on the fleshiest part of Sousuke’s bottom lip and tugging gently.

He pulls away just as Sousuke’s breath hitches and leans in close to his left ear, in a mimicry of what Sousuke had done before. He’s more than a little pleased to discover that Sousuke’s muscled form trembles at the motion too.

“I just want you to fuck me.”

Sousuke’s tail jerks violently at that and consequently presses into Rin’s crotch with the most delicious kind of pressure. Rin can hear him panting, loud and wet in the silence of the night air.

“ _Rin_.” He says, and then nudges Rin’s thighs even further apart with his broad palms, till they’re stretched out wide and open on either side of Sousuke’s waist. In an embarrassed, reflexive motion, Rin tries to bring them back together, but Sousuke’s iron grip on them barely lets him move an inch.

The cool night air is brushing against parts of him that he’d  _really_ rather not leave exposed, but Sousuke’s mouth on his navel diverts his attention from that pretty quickly. He must have shifted down while Rin’d been caught up in his own embarrassment.

Sousuke's tongue swirls into the indentation of his belly button and Rin clutches weakly at the sand on either side of him at the roughness of that tongue against his own smooth, hairless skin. When he brings his fingers down to tangle into the fluffy mess of Sousuke’s hair, Sousuke breaks away from his ministrations and chances a glance up at him.

His eyes are just as intense as they’d been a couple of minutes ago, but there’s a new kind of franticness in them now, and Rin groans when he swipes his tongue across the corner of his lip in an unconsciously, terribly seductive gesture.

“Can I?” He asks, fingers making an agonizingly slow path to where Rin needs them the most.  His voice is gravely and soft.

“What kind of question is that?” Rin mutters furiously, and then keens louder than he’d have liked the very next second, because Sousuke has leaned in to close his lips over the tip of his dick.

“Oh my god, oh my god.” He scrunches his eyes shut and focuses on breathing steadily, because he’s still a hopeless, eighteen year-old virgin boy, and even looking down at Sousuke’s beautiful face and his own dick in the same frame of vision might be enough to end this encounter disappointingly quickly, much less watching those lips doing wicked things to his dick. “When I said you  _could_ , I had no idea you meant-“

His desperate groan cuts his words off because Sousuke’s lapping at his dick leisurely now and rolling his heavy balls around with a curious palm.  Rin cracks his eyes open, overcome by the intense pleasure, but still wanting to keep this in his memory for many a future wank session. And then breathes heavily through his nose in a mighty effort not to do something embarrassing like knee Sousuke in the face or maybe  _pass out_.

When he’s finally at the point where he thinks he might not come the very next second, he watches Sousuke, thumbing over his cheek and smoothing out his eyebrows as he takes Rin’s dick impossibly deep inside his mouth. 

“Guess mermen don’t have gag reflexes after all.” He manages to murmur faintly, as he feels Sousuke’s throat convulse around the tip of his dick. His belly clenches so tightly that he’s afraid it’s going to be stuck in that weird contortion for the rest of his life, and he has to curl his toes and fingers into the sand with the sheer effort of not coming right then.

“Fuck!” His own voice rings in his ears, too loud and frantic, when Sousuke takes his reaction as a cue to go on, and slides further down onto his dick. His mouth and throat are warm and clutching around his dick, and Rin watches his tail twitching restlessly behind him. “Okay, okay, you’ve got to stop.”

He grasps Sousuke’s jaw with a palm and pulls him off his dick carefully, before reaching out to the bulky backpack on his left and tugging it closer by its strap. With his other hand, he pulls a reluctant, rapidly blinking Sousuke up until he can kiss him chastely. He tastes oddly salty, and Rin grimaces faintly when he realizes that it’s himself he’s tasting.

“You- Uh, you didn’t like it?” Sousuke asks, eyes darting between Rin’s left eye and right, in a nervous little tic. “I mean, I don’t really know what to do. This is just what they did in the video we watched that day, but uh- Maybe I didn’t do it deep en-“ Rin silences him a soft press of the pad of his finger to his busily moving mouth.

It’s more than a little endearing to witness this side of Sousuke, all the more because he’d been an irritatingly confident (and unfairly attractive) lover earlier on and Rin had been worried that his own inexperience would be off-putting. The renewed knowledge that Sousuke is still a virgin for all accounts and purposes, reassures him and makes him feel strangely tender towards the bumbling mess of a merman peering down at him unsurely.

Those eyes are  _surely_  made of magic, Rin thinks absently, as he dazedly locks his gaze onto the hypnotizing swirls of silver, ringed by the barest tint of teal, drawing him deeper and deeper into them. It feels like there’s no way out and Rin is drowning, unable to tear away his gaze and-

Someone jostling him roughly breaks him out of his trance.

“Oi, don’t do that!” Sousuke’s eyebrows are drawn down low in worry and what looks almost like self-consciousness. “Don’t do that for too long.” He repeats, voice subdued.

“What, why?” It’s starting to dawn on Rin right then, that just maybe, his trance-like state from earlier had not just been due to Sousuke’s unfair beauty, but rather  _induced_  by something.  _Knew it_ , Rin thinks a little smugly,  _he has freaky merman powers after all_.

“I dunno, Mam always told me we could hypnotize humans by holding their gazes for long enough. Make them do whatever we want them to, you know? Or even make them forget they met us at all.” Sousuke shudders at that and Rin kisses his cheek sympathetically.

“Don’t worry, I’m not gonna be forgetting about you anytime soon. Especially not with  _this_  problem.” He nudges his hips up insistently into Sousuke’s, sighing happily as his erection presses against the hard ridge of Sousuke’s hip.

“Next you’ll be telling me you’re a siren. Is that how you’ve been getting me to the beach every single day. Huh?” Rin bites at his neck playfully and nuzzles into the ticklish part of his sternum just to hear Sousuke’s muffled snorts of laughter and feel him squirming.

“No to that one, unfortunately.” Sousuke entwines his fingers with Rin’s own and grins at him. “That's Kisumi. But he’s not a very good siren, you probably would’ve realized. He just makes the poor girls eat dinner with him every night instead of drowning them. And then sends them home before daylight.”

Rin rolls his eyes at the mention of that overly affectionate, bone-meltingly cheerful parody of a mythical creature. 

“Tell him that if he dares to pull my sister to the beach one more time with that awful wailing, I’m gonna cook him and eat him during our family dinner.”

Sousuke’s tail curls in, possibly out of some perverse sympathy for his fellow fish-tailed buddy, and Rin snickers and pulls him into a languid kiss. He reaches into the backpack that he’d pulled towards him earlier and fumbles with the side zip until it slides open. And then blindly gropes about till his fingers catch on a smooth, long surface.

Sousuke musn’t have noticed his distraction, because he’s still very enthusiastically licking into Rin’s mouth. He startles when Rin slaps the tube of lubricant onto the center of his back with a loud thwack and then shoots Rin a mildly disgruntled look. He has to stretch one of his hands behind him to retrieve the tube, and Rin takes a couple of seconds to appreciate the flex and strain of his impressive triceps as he holds himself up with a single arm.

Sousuke tosses the lube onto Rin’s chest once he retrieves it and raises a curious eyebrow at him.

“What’s this? Am I allowed to touch this one or..?”

“If you don’t touch this, we’re gonna have a very big problem.” He squints down at Sousuke’s erection. Still there. Still  _very_  substantial. Still very much going inside of him.

He takes in a deep breath to calm his newly agitated nerves.

“You’ve gotta use this to ease the way, Sousuke. I’d use my own fingers first but,” He sticks out his tongue in a vaguely disgusted expression. “I’m kinda squeamish.”

Somehow, the thought of sticking his own fingers up a place where stuff usually came out, aggravates his discomfiture. That it’d looked pretty damn painful to even  _watch_  in the short videos Rin had downloaded from that shady webpage, hardly made matters better.

Sousuke agrees quickly though, to his utmost surprise. Rin supposes mercreatures were less concerned about stuff like this. They’d have to be, what with picking up slimy bits of seaweed for dinner, eating fish raw and having to find  _very_  creative means of excretion in the deep, deep blues.

“Do I just-?” In Rin’s moment of distraction (he should’ve known better, honestly, because in all the time that he’s known Sousuke, he’s come to realize that leaving him unsupervised with dubious objects meant for human use is a singularly bad idea) Sousuke’s managed to rip the top off of the tube instead of unscrewing it like a civilized being, and Rin has absolutely no time to warn him before he presses hard right into the bulky middle of it.

Rin shields his eyes with a forearm as the goopy slick flies everywhere. When the storm’s passed, he wipes the sticky back of his hand against Sousuke’s flank disgustedly and clicks his tongue.

“Why am I not surprised?” He mutters, and he doesn’t even have to look up to make out Sousuke’s innocent grin. “Don’t answer that.”

Sousuke seems to have grasped the basics of lube, for all that he’d seemed like a block-headed idiot just seconds ago. He smears the copious dribbles of slick on his palm onto his fingers and then swipes them across Rin’s belly to gather the excess stickiness pooling there.

When Rin adjusts his legs around him restlessly, Sousuke stills them with a broad palm to each thigh and then wraps a hand around his own erection to give it a few, leisurely tugs. Rin watches him bite his lip, watches his chest rise and fall with his rapid breaths, acutely feels the spidery, wet touch of his fingertips as they trail down to his hipbone and brush over his dick before slipping lower.

When a fingertip prods at him, Rin has to bite back a tiny, panicked noise. He suddenly thinks that it’s not going to go in, that all of this is going to end up a mess, that he won’t be able to take Sousuke’s fingers, much less his dick. His mind is a whirl of ill-contained panic and he’s just about to bite out the words that’d signal for Sousuke to stop when Sousuke’s finger slides into him slowly.

Rin breathes in deep and focuses on not making jerky movements. To calm himself down, he directs his gaze to Sousuke’s eyes, that strange, alluring hybrid of sea-blue and silver. Sousuke’s gaze is focused on where his finger has slid in to the hilt now, and his nostrils flare almost agitatedly when Rin tenses around him.

It’s strange, the feeling of having something inside him, he can’t deny that. But it’s nowhere as bad as Rin had thought it to be, just vaguely uncomfortable, so he focuses on counting his determinedly even breaths and keeping his gaze on Sousuke’s dark hair, the way his forearm flexes in a distractingly arousing manner as he fingers Rin, how his beautiful tail looks like nothing remotely from this world as it sifts through the shallow water breaking at the shore. Vivid scales catch the moonlight at odd angles and Rin is ensconced in a vaguely dream-like moment where he’s left wondering if it were only Sousuke’s eyes that held the power to hypnotize unsuspecting humans.

He wouldn’t even have noticed Sousuke nudging a second finger in, if not for the vague sting of it. Sousuke’s free hand comes to pet at Rin’s hip when he twitches restlessly and bites his lip, and Rin grabs at it with his own, squeezing it tightly just once and then tangling his fingers with Sousuke’s own.

When Sousuke furrows his eyebrows and twists his fingers into Rin in an experimental movement, Rin’s entire torso jerks at the fleeting jolt of that indescribable feeling. 

“What?” He asks, dazed eyes darting up to Sousuke’s. “What was that?”

Sousuke doesn’t reply. His gaze skims over Rin’s half-lidded eyes, drags down the slope of his nose to his parted mouth, and Rin watches his eyes as they move closer and closer to his own. He could’ve sworn they’d flared an even brighter shade of silver just a second ago, but it could have been the moonlight playing tricks on his eyes, so Rin just angles his head and mouths at Sousuke’s lips languidly.

“This is nice, isn’t it?” He murmurs, tilting his neck to Sousuke’s touch as he kisses wetly at the pulsing vein at his jugular.  Sousuke just hums in reply, and the sound makes Rin’s already heavy eyelids droop shut.

His eyes snap open and he twists away though, when Sousuke tries to nudge a third finger in, but Sousuke just nuzzles into his neck and pets his flank until Rin goes still, thrumming with a kind of fearful anticipation. He already feels stretched tight, Sousuke’s thick fingers filling him up to the the point of uncomfortable fullness, and occasionally nudging at a spot inside that makes saliva pool in his mouth and his breath grow shorter.

He’s not sure if he can take much more. But Sousuke nudges his knees further apart, until Rin is splayed out in a positively obscene posture. He can feel the stretch in his hip flexors and in the trembling muscles of his thighs.

It’s odd how Sousuke’s gone completely silent, but Rin hardly takes note of it, not when his beautiful fingers are slick and hot and  _huge_  inside of Rin, twisting and stretching and pushing in till he thinks he can barely differentiate between the dull ache and the jolts of pleasure.

Sousuke’s left hand comes to wrap around Rin’s bobbing, flushed dick, this time slippery and cool with the spilled lube, and Rin scrunches his eyes shut at the overload of sensations. He wants to ask Sousuke to stop, that it’s too much, that it’s not enough, wants to yell at him to go faster, take more, and more and more until Rin has nothing left to give.

Not a sound escapes Sousuke’s lips all the while, and Rin finally takes notice of his odd reticence (he comes off as aloof and intimidating to human strangers, but not to Rin, never him). When he cracks his eyelids open and chances a glance at his face, what he finds there makes his heart leap partly in apprehension, but mostly in a rapidly escalating sort of excitement.

The skin beside Sousuke’s eyes has gone a gleaming turquoise, and when Rin reaches up tentatively to smooth at it, he feels the rough scaly texture of it, almost identical to his tail scales. His pupils have become vaguely slitted, and they’re a molten silver now: the hints of blue from before nowhere to be found.

When Rin glances down, he finds the same roughness of scales lining his fingers and the meat of his forearm. Rin thinks that it speaks volumes about his own sick psyche, that he feels inexplicably aroused by Sousuke’s sudden physiological changes.

“Sousuke,  _fuck_..” He murmurs, and Sousuke just smirks at him, breath coming in cloudy exhalations. When Rin lifts a palm to his mouth, he feels the impossible warmth of his breath, easily five or more degrees up from his usual temperature.

“Alright, alright.” He tells himself frantically, snatching his hand back and yanking Sousuke’s neck down to catch his lips in a wet, open-mouthed kiss. He marvels at the heat of Sousuke’s mouth, it’s slick and  _hot_ inside, not warm like the inside of a regular person’s mouth.  Guess those freaky merman powers come in pretty handy on cold nights, he thinks vaguely.

When Sousuke’s dick nudges between his thighs, he grips those solid shoulder blades hard and draws in a breath through his nose.

“Okay, now. Do it before I change my mind.” He breathes into Sousuke’s ear and shuts his eyes.

The tip of Sousuke’s dick is malleable and soft when it presses into Rin, and Rin bites at the inside of his cheek to hold in the keen that’s building up in his throat. When Sousuke leans down to press his hot lips to the curve of Rin’s shoulder, Rin hugs his torso to himself and tries to burrow into him.

It’s funny, he thinks, how even when Rin’s trying to protect himself from Sousuke, it’s Sousuke that he turns to. He’s Rin’s safe place, and Rin aches at the thought, of the possibility of not being able to come home to him one day.

He’s a human being with an infinite realm of possibilities stretching out before him,  with a smattering of childhood friends that he holds close to his heart, a promising swimming career in wait and a doting mother and beautiful sister back at home, but he thinks selfishly just for a moment, of all the things he’d give up to stay in Sousuke’s unnaturally warm embrace.

“Rin..” He whips his head up at Sousuke’s soft voice and smiles at him when he notices the worry in his almost unrecognizable eyes. It’s obvious he’s trying to hold back for Rin’s sake, and Rin pats his cheek fondly and nods for him to go on.

When Sousuke pushes in a little furhter, Rin realizes abortedly that he hasn’t yet coated himself with lube, and begins flailing. He relaxes though, when the thickness of Sousuke’s dick slides into him inch-by-inch, with surprisingly little resistance. He recalls the slickness of his dick from earlier, the vaguely membrane-y looking fluid coating it. It acts like lube, he realizes with a start.

Sousuke’s dick is hot, just like the inside of his mouth, and it burns a path into Rin’s insides as Rin squirms restlessly against the deliberate movement of his hips.

“I-I can’t-“ Rin bites his lip viciously, tasting the fresh, coppery tang of blood. “How much more?” He manages, because Sousuke is  _huge_ and even though Rin’s insides feel slick with the strange liquid coating Sousuke’s dick, he doubts that he can take much more of the near-painful pressure.

Sousuke just slows his motions and reaches a finger down to where Rin’s stretched and hot around his dick. When he uses the pad of his index finger to rub at the taut skin around his entrance, Rin whimpers and pushes into the distracting touch.

Sousuke keeps at it, swiping some of the viscous fluid off his own dick and massaging it into where Rin’s sensitive and hurting. It helps, just that little bit and Rin relaxes minutely and lets more of Sousuke in. When he props himself up on his elbows and peers down, he notices belatedly that even Sousuke’s dick (or at least the part of it that isn’t already inside Rin) is lined with the strange blue scales.

That would explain the odd roughness of it against the sensitive skin of his insides despite the superfluous slick, Rin thinks a little wildly.

Sousuke’s index finger hooks on one side of the loosening skin of Rin’s entrance and tugs gently right then, and Rin’s eyes go wide with the sensation.

“C’mon, just open up a little – for – me, Rin.” Sousuke punctuates his words with tiny, careful thrusts forward, and Rin’s eyes roll back into his head with the pleasure-pain of it all. The roughness of the scales lining his dick and the coolness of the fluid he’s secreting inside Rin are sensations magnified a thousand times over, and Rin brings his knees up and hooks them up against Sousuke’s tail; grounds himself with the rough scrape of Sousuke’s scales against his bare, smooth kneecaps.

“Sousuke, you bastard!” Rin gets out in a strangled voice, too shaky and soft for his own liking. “How long is your dick anyway?”

Sousuke laughs lowly, but Rin shivers when the movement shifts his dick inside of him and intermittently presses his abdomen against Rin’s erection. Sousuke just pushes forward the tiniest bit, until Rin can feel him nudging up deep inside of him, so deep that Rin thinks he’s going to feel the ache of him inside for days, weeks to come.

“All in.”

Rin lets his elbows give out at that and he collapses onto his back in relief. And then whines at the jarring shift of Sousuke’s dick inside of him.

“Sousuke.”  He tries to catch his breath. “If I die from this, how are you gonna get me back to Ma so that she can do my funeral rites? You have a  _tail_.”

Sousuke huffs again in amusement and leans in to kiss the tip of Rin’s nose.

“Stop being dramatic, Rin. No one’s gonna die.”

Rin takes just a moment to look into his eyes, so wide and close to his own, before he rips his gaze away, lest he get caught up in his hypnotic fish mojo again.

Sousuke grins at him in that lopsided, endearing way that makes him look acutely boyish and all of sixteen again.

“Besides, I’m not sure your Ma would even  _want_  to do your funeral rites after she finds out how you died.”

Rin has to chuckle at that. Ma is hardly the conservative type, at least not when compared to the rest of the middle-aged mothers in Iwatobi, but Rin thinks that even she might have a bit of a tough time digesting the likes of whom Rin has been consorting with.

“You’re probably right. Even if I survive this, I doubt you could just waltz up to our front door and ask her for my hand in marriage. I mean, what will you even wear? I’m pretty sure there’re no pants that come in size  _tail,_ for one.”

Sousuke brushes his wet hair away from his eyes and leans in to kiss him silent, and then nudges his hips into Rin’s gently until he’s left open-mouthed and panting.

Rin acutely feels every thrust that Sousuke makes from then on, because he’s just on the right side of full, and impossibly slick with the strange liquid that Sousuke’s secreting in copious amounts. The muscles lining Sousuke’s solid tail tremor under Rin’s thighs with every thrust, and Rin twines his legs tighter around it in wordless response. It feels like he can’t wrap himself tight enough around Sousuke’s warm, huge presence.

Sousuke’s palms are sliding against the fine sand on either side of Rin’s head from the jarring power of his own thrusts. It feels like forever before he nudges up against something inside of Rin that makes his vision go hazy for just a couple of seconds.

“Do- do that again.” He grunts, digging his blunt nails into the meat of Sousuke’s shoulders, where unsurprisingly, silvery blue scales have started to make their appearance.

Sousuke smiles at him, slow and deliberate, and then does it again. Even through the haze of pleasure, Rin is just barely lucid enough to gape open-mouthed at that surreal face, too regal and beautiful to be mistaken for anything remotely human.

“Rin.” Sousuke moans, nosing into the crook of Rin’s neck first, and then his hair and then the sensitive patch of skin behind his ear. “Rin, you smell incredible.” His warm breath tickles Rin’s ears, but Rin is too caught up in bucking his hips into the force of Sousuke’s steady thrusts to squirm away from the sensation.

He pants and pushes his neck into the warm, blunt grasp of Sousuke’s teeth as they clamp down carelessly onto the tendon standing out in stark relief. He barely feels the sting of it, not when Sousuke’s thrusts come perfectly-aimed and steady now, nudging up deep inside him and rendering him speechless.

“Touch me.” He manages to whisper, amidst the slick sounds of their coupling, and Sousuke does.

He holds himself up with his right arm and uses his left to jerk Rin off with quick, efficient flicks of his wrist. Rin goes desperate with desire, littering chaste kisses onto Sousuke’s arm, where it’s flexing beside his head, and then licking at his jaw and then his reddened lips. 

Despite all of Rin’s flailing and squirming, Sousuke manages to keep up the tempo of his thrusts, and Rin can feel him inside, the feel and texture of him somehow alien and incredibly arousing. He pushes up into Sousuke’s hips and hands, and Sousuke’s hand on his flushed dick is moving so quickly, the motion is almost a blur to Rin’s dazed eyes.

“What the fuck? Do you have super-speed too?”

“No.” Sousuke pants, eyes focused and intense, mouth compressed into a firm, devastatingly attractive line. “Unfortunately not.”

He leans down to kiss Rin, probably to shut him up, Rin thinks a little crabbily. Rin doesn’t close his eyes this time, too drawn to the gleaming mercury of those irises swirling in abstract patterns.  All he can see is silver, silver, and the barest hint of blue, and Sousuke’s mouth is moving but all he can make out is that all-consuming hue, beckoning him closer, closer.

Sousuke tilts his gaze away with a palm to his cheek the next second.

“Stop that, you idiot.” He huffs, and then gives a particularly sublime twist to his wrist; one that makes Rin’s fists clench in his hair roughly.

When Sousuke thrusts in again, it’s deep and slow, and Rin just adjusts his limbs around him, hanging on for dear life.

“So close.” He nips at Sousuke’s ear, barely even feeling the grainy sand particles slipping between his thighs, sliding over his shoulders and back uncomfortably.

And then Sousuke yanks Rin’s thigh further up on his waist and pushes in hard and fast, locking his gaze onto Rin’s own.

“C’mon, Rin. Come for me.” He releases Rin’s dick and scrapes a blunt nail over the rim of him, where he feels sore and stretched. The sensation spikes through every one of Rin’s veins and Rin makes a gurgled, helpless sound at the back of his throat.

When Sousuke looks him in the eye, Rin makes out his own flushed, lewd expression in the reflection of that silvery gaze.

He comes silently, mouth parted in an obscene ‘o’.

Sousuke’s lip twitches in satisfaction, and he smooths at Rin’s inner thigh with the pad of his thumb, watching Rin intently as he rides out his climax, sticky come splattering all over his abdomen and outer thighs.

“Need to work on that endurance, eh Rin?”

Rin’s too drunk on the pleasure of his climax and the sore fullness of Sousuke throbbing inside of him to even grace that with a vocal response, but he flips him off weakly nonetheless, and then guides his hand down to rub at the base of Sousuke’s dick, where it’s pressed to Rin’s entrance, questingly.

Sousuke makes a throaty sound at that and digs his nails into the flesh of Rin’s thighs, bending him forward until Rin’s hair is smushed to the sand and his legs are embarrassingly high up in the air.

“Big talker.” Rin grumbles, partly in an effort to hide his embarrassment at being contorted into such an embarrassing and  _indecent_ position.

“That’s not the only big thing about me. But you’re taking it pretty well.”

And Rin should’ve seen that coming, he  _really_ should have, but he groans and slaps at Sousuke’s scale-lined cheek weakly. Sousuke talking sex to him comes as something of a surprise to him. And also an incredible turn-on, if he’s being honest, but he’d much sooner peel the skin off his own body than admit that to him, so he just squeezes around Sousuke instead, gasping at the pinpricks of sensation that resonate through him.

Sousuke’s eyes narrow and his tail swishes behind him, sending droplets of water spraying onto Rin’s calves first, and then, as the movements get increasingly intense, into his eyes. He blinks away the sting of the salt, hiding his face in Sousuke’s neck to muffle his whimpers as Sousuke continues pushing into him.

He’s oversensitive and his skin feels too tight stretched across his limbs, but it’s  _Sousuke_ here with him, here inside him, in more ways than one, and Rin isn’t sure why this feels like the first and last time, but he doesn’t want to ever let go of this feeling.

He startles when cool water laps at his toes though, and then grunts as one of Sousuke’s particularly skillful thrusts find that spot inside of him again. His dick gives a weak twitch, but stays limp, draped across his thigh.

“Shit.” He mutters. “Sousuke, the tide’s coming in. You gotta hurry.”

Sousuke looks like he’s hardly noticed Rin’s frantic whisper, just continues dicking into Rin with that almost frightening intensity.

“Sousuke!” He says, louder, more urgently.

“Just a little more, Rin, just a-“ He grips Rin’s wrists tight enough that Rin feels the ache deep in his bones, and pins them to the sand.

Rin squirms under him when the salt of the sea water begins stinging at the skin of his newly shaven calves, but then goes limp when Sousuke turns a distracted, tight smile to him.

“Okay, yeah just like that.” Rin murmurs, feeling awkward and a little bit silly, but too caught up in the moment to care. “Just come inside me.”

“You’d like that, wouldn’t you?” Sousuke answers, grunting with the force of his thrusts in, and then his torso goes taut and still on top of Rin’s.

Rin shudders when he feels the hot warmth of him inside, and bites his lip when Sousuke’s tail curls in pleasure around his calves.

Sousuke’s breathing is deep and slow in his ear and Rin takes a moment to collect himself, to calm his racing heart. The water is up to his waist now, and Sousuke’s tail is sliding languidly through it, creating tiny ripples as it cuts through the clear surface.

Rin only starts to feel the sheer weight of him after a couple of minutes, and he kicks at Sousuke’s tail weakly, his chest heaving with the effort to breathe and his insides feeling sore and cramped.

“Okay, fun time’s over, you need to move now, moron.”

Sousuke doesn’t even grunt in reply. Rin feels his slow, rhythmic breathing tickling the lobe of his right ear.

A creeping feeling of dread starts washing through him, and he tries pushing at Sousuke’s shoulders, eyeing the rapidly rising tide warily.

“This isn’t funny. Wake up, Sousuke!”

He can’t squirm out from underneath him in the next few moments, no matter how much he kicks at him or tries to heft Sousuke’s massive form off of his torso. When the water laps at his neck, he takes a deep breath and leans forward to nudge his mouth up against Sousuke’s ear.

“ _Get the fuck up_!” His throat strains with the volume of his hoarse yell, but it does the trick. Sousuke jerks backwards and then lifts up on his forearms and blinks at Rin rapidly, eyes dazed and confused and back to their regular, beautiful blue.

“What? Rin?” He asks, mouth twisting into an unhappy moue at being interrupted from his fucking  _beauty sleep_.

Rin rolls out from under him, flinching at the tender ache as Sousuke’s dick slips out from him, and then scrambles towards the dry shore frantically, collapsing against the soft, dry sand once he’s managed to crawl a good distance away from the freezing water.

“You complete idiot.” He tells Sousuke, heart still hammering wildly. “ _You could’ve ended me_!”

Sousuke has the decency to look a little sheepish at least, but Rin slaps his fingers away when they come to brush against his cheek apologetically.

“I can’t believe you actually fell asleep.” He mutters disbelievingly, watching as Sousuke’s cheeks flush. “After all that earlier.”

“Well it  _is_  late out.” The big moron wheedles, and Rin frowns at him until he can almost see his metaphorical ears and tail droop in dejection.

“Stop pouting, you’re a fish not a damn dog.”

“I’m not a fish, Rin!”

“Yeah you’re even worse. You’re  _that_  fish. The one that falls asleep after sex and nearly kills his human.”

“My human, huh?”

“Out of that entire sentence, you chose to pick that out? Really? What about the attempted murder part?”

Sousuke just smiles at him guilelessly and Rin sighs and holds out a hand to him.

“Fine, fine. Come on, come lie with me for a bit. You’ve ruined the moment of post-coital bliss anyway.”

Sousuke shimmies up to him, his swaying tail splashing water all over Rin and making him splutter. And then wraps his big, warm arms around Rin’s chest, pushing his fluffy head into the crook of Rin’s neck like a puppy.

It’s unfair how it’s impossible to stay angry at him, Rin thinks bitterly. He tells himself he's only letting Sousuke cuddle in close because he's the idiot who got him completely drenched in the first place and Rin doesn't particularly feel like heading into a bout of hypothermia in the middle of the night. When Sousuke makes a soft, contented noise, Rin adjusts his sore back on the bed of sand and begins carding his fingers through Sousuke’s hair.

“Hey Rin?” Sousuke’s voice is muffled by the skin of Rin’s neck and Rin yawns in response and scratches at his scalp lightly.

“Hm?”

“Sometimes I wish I were human.”

Rin’s eyes, which had been drifting closed slowly, snap wide open again.

“What? Why in the world would you want to be _human_?”

“So that I can be with you.”

Rin chuckles and pinches the tip of Sousuke's nose till he squirms out of his grip restlessly and props himself up on his elbow to look down at Rin with serious eyes.

“Well, last time I checked, you had a tail, but you’re still here with me.”

Sousuke makes a tiny noise of protest.

“Not like that. I want to  _be_ with you, Rin. I want to meet your Mum and go for picnics in the gardens you always talk about. I want to run with you every morning, I want you to be proud when you talk about me with your friends.”

Rin’s chest clenches at the softness of Sousuke’s voice, the despondency resonating through it.

“I don’t just want to just be a novelty or an adventure to you. I don’t want to be your pet.”

Rin feels the sting of his words like a slap. His nostrils flare indignantly and he pushes himself up with his palms to the sand, ready to chew Sousuke out. Until he notices the downturned set of Sousuke’s eyes, and the way he’s drawing senseless, sad shapes into the dry sand. It makes his heart ache dully.

“Sousuke.” He smiles and tips Sousuke’s chin up with a gentle finger. “You’re hardly a phase to me. And do you really think it matters to me at this point if you’re a fish or a horse or a merman? I’m in way too deep, buddy.” He leans in to kiss Sousuke’s downturned lips, soft and slow. “You can’t get rid of me now.”

“But you could get out of here and do so many things, Rin. You could meet so many people. I can’t, I’m stuck here.”

“Too bad there’s no one else I really want to meet, then.”

“You don’t really mean that.”

Rin heaves a melodramatic sigh.

“I’m in love with you, idiot. Where could I possibly go without you?”

Sousuke blinks at him for a moment, then two, and surveys him with an unfathomable, glimmering gaze.

Rin’s fingers start twitching uncomfortably from the weight of his stare, but then Sousuke breaks out into a mischievous little grin and starts clapping obnoxiously.

“That was beautiful, Rin-Rin. Am I supposed to cry now?”

Rin slaps him on the upside of his head and laughs a little, seeing right through him.

“Just say it back, you damn sushi roll!”

Sousuke leans in to kiss him, cheek reddening rapidly. His face is clear and rosy again; there’s nary a hint of the blue-grey scales from before.

“I love you, Rin. And I won’t hold it against you if you ever change your mind, but I really want to be by your side.”

Rin’s heart lurches at the warmth in his voice, at the impossibly light hue of his drooping eyes; he tries to imagine a life without Sousuke – and then chokes back the uneasy, restless feeling that rises up within him at the very thought of it.

He flops onto the sand and pulls Sousuke’s head back onto his chest, burying his nose in the vaguely salty musk of his hair and closing his eyes.

“Good thing I won’t ever change my mind, huh?” He murmurs, and watches Sousuke’s lips twitch up faintly in response. “Just go to sleep, Sousuke. I’ll move further up if the tide starts coming in again.”

Sousuke hums against him in response.

"Wake me up, I'll move with you."

He kisses the centre of Rin's chest, fingers tracing abstract constellations onto his abdomen until they eventually slow, and then stop, slackening against his skin in slumber.

The moonlit planes of Sousuke’s shoulders and the oddly pale tips of his eyelashes work their way into Rin’s most lucid dreams that night. He drifts in and out of them restlessly, the weight of Sousuke's arm on his belly anchoring him to the distant dream-shore on the horizon.

**Author's Note:**

> I didn't think I'd ever write merman dick, not even in my wildest dreams. My only excuse is: Sourin made me.


End file.
